Definition: Heterocyclic compounds in which an oxygen is attached to a cyclic nitrogen.
Other names Heterocyclic N-Oxides; Oxides, Cyclic N; N-Oxides, Heterocyclic; N-Oxides, Cyclic; N Oxides, Cyclic; Heterocyclic N Oxides; Cyclic N Oxides
2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide [ PTIO ] partial structure given in first source; endothelium-derived relaxing factor antagonist